Police have found no connections between well-regarded high-tech engineer Frederick "Fritz" Hayes and the slender bearded man who barged into his Lake Oswego-area home Monday, fatally stabbed him, then ran off.

"There is no information to lead us to believe there is any relationship between the suspect and the victim," Phillips said.

Frederick Wheeler Hayes Jr., 57, was declared dead shortly after the incident. His wife, Margaret H. Hayes, 56, was present but was uninjured.

Phillips said the relatively rare occurrence of stranger-to-stranger violence has pushed police to work around the clock.

"This is an all out effort to find this guy," Phillips said.

Phillips said a man armed with at least two knives pushed his way into the Hayeses' 3,900-square-foot home on a 1-acre lot in the 900 block of Atwater Road. After the stabbing, the man ran off and has not been seen since.

Deputies used tracking dogs and aircraft to comb the area near Atwater and Knaus roads, an unincorporated pocket west of downtown Lake Oswego. Aided by Lake Oswego police, they conducted a yard-by-yard search and interviewed neighbors. They also sought surveillance videos from area businesses and searched nearby Tryon Creek State Natural Area.

By late morning, police released a sketch of the suspect developed by a forensic artist.

Hayes' death was a shock to friends and neighbors.

Former colleague Robert McMillen, president of All Tech 1, a Tigard-based high-tech company from which Hayes recent retired, worked with him for more than 10 years.

"He was more than an employee and coworker," McMillen said. "He was a brilliant engineer and a caring mentor, and most of all, a good friend."

McMillen added that, "Fritz retired only a few months ago and was as happy as we had ever seen him as he was planning his well-deserved time off... Our thoughts and prayers go out to his family, and he will be sorely missed."

"We just haven't had things like that happen (here)," Robinson said. "It's rare that it happens in Lake Oswego -- period... Obviously it's upsetting, and I know everyone's hearts are going to go out to the family."

Immediately after the robbery, police blocked off Atwater and Knaus roads and temporarily locked down Lake Oswego High School, Lake Oswego Junior High and Forest Hills Elementary School. Meanwhile, school officials told families that it would be OK for students in those schools to miss classes Monday.

About 40 children stayed home Monday from Forest Hills Elementary School, said Principal Gwen Hill. Also, several students showed up late.

Superintendent Bill Korach said the district office fielded calls all day from concerned parents asking about status of the schools and where the attacker was.

"We kept having to give them incomplete answers to that question," Korach said, adding that classes are set to resume on normal schedules Tuesday, even if the robber remains at large.

Phillips described the robber as being in his 20s, about 6-feet-tall, with a slender build and a brown beard. He was last seen wearing a headwrap and light clothing. Phillips urged anyone who positively identifies the man in the area to call 9-1-1.

Anyone else with information should call the sheriff's confidential tip line at 503-723-4949. Confidential text messages can be sent to CRIMES (274637 on a cell phone keypad), with the keyword "CCSO" as the first word in the message.

Hayes' death is the third homicide this year in the Lake Oswego area. In June, a man was charged with killing his mother and his nephew.